Passiflora caerulea - Passion Flower
Q. I fell in love with a blue passionflower vine and decided to give it a try, thinking that it may need special care here in the NW. For the past few years, I’ve kept it in a large container near a fir tree with plastic fencing around the tree for the vine to grow up. Then I’ve taken it in the greenhouse for the winter. So far, not much luck with blooms unless it’s in the greenhouse…not my desired effect. What can I do differently to ensure outdoor blooms? And would it be wise to just keep it outdoors during the winter? I’m sitting on the fence about another greenhouse trip.
A. It’s easy to see why your “passion” fell into play on this spectacular vine. Passiflora caerulea is a definite “I must have this” plant and quite the head-turner—when it blooms. Even though this stunner comes from tropical South America, it’s hardy to about zero degrees and easy to grow here. That’s not to say you’re doing something wrong; passionflower just needs the right conditions for peak displays. It loves heat, so give it a sunny exposure with support for the tendrils to grip and climb. The greenhouse heat and light must be exactly what this pretty lady needs, as it blooms away there. You might consider moving the container to a sunnier spot, as the fir tree location may be too shady. With 4-inch blooms containing a complex structure of creamy white petals, crowned with numerous narrow filaments beginning dark purple, turning white, and ending in lavender, each flower lasts only one day. Given enough heat (key word here), it can reach 30 ft. in a single season. If we have a mild winter, the leaves will remain evergreen, but if temps go below 20 degrees it will drop its leaves and even freeze to the ground. Fortunately, it will grow back from the roots to produce summer blossoms.
Another tip…. Consider taking it out of the container. Planting in moist, good draining soil that is loose and even gravelly is essential. Passiflora blooms on new growth and should be pruned in late winter/early spring; however, no regular pruning is necessary. Go light on fertilizer and compost, which will encourage foliage rather than flowering. Encourage your passionflower to reach down into the earth for water for a powerful root system to help it through the winter. Another recommendation is to keep the vine on the dry side in winter—a tough task in the NW, but covering with branches or mulch will slow down the rain absorption. One other tip: Don’t try to train this wanderer to be too neat and compact, as the branches allowed to hang loose and droop a bit will be the ones that pop with flowers.
Lucky you! This variety isn’t often available at local nurseries, but many other hardy varieties out there have multi-colored and fragrant blooms. This variety may be a bit of a Zone-pusher (hardy in zones 9- 11), but is often root-hardy in Zones 8 and 7, if well sited and heavily mulched in winter. Are you a risk-taker? If so, free this passionflower lovely from its winter container hibernation and await the rubber-necking views. Let the climbing with abandon begin. As a backup plan, passionflowers can be easily propagated from stem cuttings. Just sayin’
Courtesy of M.P. Redmond Garden Club Member